In certain instances the welding operator is confronted with limited access to the weld location requiring the operator to awkwardly position the torch in order to perform the welding operation. An obvious solution to this problem would be to use a flexible guide which is manipulatable into any position for guiding the direction of the electrode wire through the nozzle of the welding torch where current is supplied to the electrode before it contacts the weld joint. A flexible extension for use in conjunction with a nonconsumable welding electrode gas shielded arc torch is shown and described in U.S. Pat. No. 3,158,730 which issued on Nov. 24, 1964 to C. W. Hill and entitled Gas Shielded Arc Torch. The flexible assembly described therein consists of a bundle of elongated flexible solid metal wires which extend in a spiral configuration between the torch body and the nozzle. The bundle of wires provide flexibility as well as perform the function of transmitting current from the torch body to the nonconsumable electrode located within the nozzle. The specification teaches how to correlate the number of strands and size of flexible wires needed to achieve a high degree of rigidity at any chosen angular position with desirable life and weight characteristics. This teaching can be directly employed in the design of a gas shielded consumable electrode arc torch by using the flexible neck region of the torch as a conduit to provide passage for a movable electrode as well to provide control over its direction. A straight forward design would simply involve arranging the bundle of strands of wire around a cylindrical sleeve innerliner which would form an annular passageway for the electrode. Such a design would not, however, adequately account for any tendency of the multiple strands of wire and innerliner to kink or crimp during bending of the flexible neck. The effect of such kinking or crimping would be to greatly increase the feed forces required to drive the electrode through the torch body.
One design directed specifically to a consumable electrode flexible wire guide attachment for a gas shielded torch and which is intended to minimize the tendency of the wire guide to kink during bending is shown and described in U.S. Pat. No. 3,755,648 issued on Aug. 28, 1973 and entitled Flexible Welding Nozzle Apparatus. The patent describes a flexible wire guide consisting of a twisted bundle of wire strands arranged about a steel spring which forms the bore through which the electrode passes. The wire strands are constrained by an outer glass tape support sleeve. The tape sleeve is intended to prevent the coiled strands from spreading during bending whereas the spring liner is intended to applied a radially outward force to maintain the circularity of the bore. Apparently whatever benefit is derived from the constraint placed on the windings comes only at the expense of flexibility in manipulating the wire guide attachment. The greater the constraint the less flexible the guide becomes and the greater the increase in spring back from a bent position.